3D rendering is usable in various fields such as a 3DTV, 3D displays, 3D games, 3D glasses, and so forth.
Virtual Reality/augmented reality are particularly facing the issue of correspondence between the real and the virtual world and can benefit from the embodiment of the present disclosure as well.
The embodiment of the present disclosure improves 3D representation (by means of adjusting disparity between pictures) in stereoscopic or autostereoscopic images in order to better fit the natural viewing geometry.
Classically, for rendering, pinhole camera models are used which are not in accordance with the way human eyes capture and exploit angles in space for depth perception.
According to the present embodiment, a new model is used taking into account individual characteristics to modify the projective geometry.
Today, the prevalent 3D content creation model is the double perspective projection (or double pinhole camera model). It is widely used for both synthetic and natural content, either as a GCI camera model, or as a representation model for real cameras. It is used as well as basis for 3D image processing of many sorts.
As shown in FIG. 1, perspective projection predicts x/d=X/D and y/d=Y/D for each of the two eyes.
Binocular observation is classically modeled by a double perspective projection, one corresponding to each eye or camera directed perpendicularly to the eye plane.
With this model, as shown in FIG. 2, the disparity Δx between views for a point to be shown at a distance D and for a display at a distance d is predicted to beΔx=(e·d)/D  (1)
where “e” is the interocular (or inter-pupillary) distance.
Today this basic pinhole camera model is widely used to design cameras, in 3D computed generated imagery (CGI) or for 3D images or video processing. This generates 3D images and video with scale/depth distortion or incorrect 3D perspective and motion distortion when compared to human vision.
Compared to natural viewing, the pinhole camera model creates images more difficult to visualize, although they are accepted as 3D images by the human visual system. That is, the correspondence with the natural space is only partial, valid only for small visual angles around the attention point.
Some solutions have been proposed to attenuate the annoyance (depth scaling/image scaling) such as a solution previously proposed by the applicant giving control of depth strength to the user, or as in the following paper:
“Mapping perceived depth to regions of interest in stereoscopic images”, N. S. Holliman, in Stereoscopic Displays and Virtual Reality Systems XI, Proceedings of SPIE-IS&T Electronic Imaging, SPIE Vol. 5291, 2004” (see http://www.dur.ac.uk/n.s.holliman/Presentations/E15291A-12.pdf)
The objective of the present embodiment is to improve a projection model in order to obtain a better 3D representation and rendering for a better spatial matching between an intended (designed or captured) space and its representation on a 3D display. As a result, the 3D rendered objects will appear more natural to the observers.
According to the present disclosure, an observer's view is modeled independently for the left and right eyes, and the left and right views are processed independently with the goal to
re-align pixel directions for each of eyes to make these directions more in correspondence with natural vision for the observer.